age (21.6 [3] years vs 22.4 [3] years), sex (66% vs 79% male), or mean (SD) past-month quantity of alcohol use measured using a 30-day timeline follow-back method (72 [50] vs 72 [41] standard drinks). Mean breath alcohol levels after each of the 3 drinks were 0.018%, 0.038%, and 0.055% and did not differ by genotype. To ensure that population stratification was not a confounding factor, analyses were repeated with only the white individuals. No differences emerged.
